A data transmission rate of a wireless communication system is limited by a radio spectrum. To save a data transmission bandwidth, when the wireless communication system transmits multiple streams of Time Division traffic, a bitmap is used for indicating a number of streams of Time Division traffic data transmitted on a time slot under consideration, and a bit width of the bitmap is used for representing a maximal number of transmitted streams of Time Division traffic data supported by the system. When the wireless communication system supports eight streams of E1 traffic, a bitmap thereof will be 8-bit wide. The eight streams of E1 traffic data may be transmitted in a frame format as shown in FIG. 1, where a time slot under consideration may include five streams of E1 data packets, i.e., a first, a third, a fourth, a fifth, and an eighth stream of E1. Then, the bitmap may be 10111001, meaning that subsequently a first E1 fragment is the first stream, a second E1 fragment is the third stream, a third E1 fragment is the fourth stream, a fourth E1 fragment is the fifth stream, and a fifth E1 fragment is the eighth stream. A E1 fragment numbering thereof is a Channel Number (CN) of the E1 data. The CNs and the E1 data are to be transmitted simultaneously to the wireless communication system.
In related art, a bitmap is used for representing a frame structure of Time Division traffic. For example, a structure for receiving eight streams of E1 data is as shown in FIG. 2. According to the bitmap, a stream of E1 data may be placed into a First Input First Output queue (FIFO) with a FIFO number corresponding to the number of the stream of E1 data. For example, the first stream of E1 data may be placed into a location indexed by FIFO Number 1, the third stream of E1 data may be placed into a location indexed by FIFO Number 3, and so on. Then, during data reading, a stream of E1 data may be read from a FIFO with a corresponding FIFO Number. However, such a frame format may be disadvantageous for reasons as follows.
Firstly, FIFO pointer control during data writing and reading is complicated. When the number of routes of Time Division traffic supported by the system is increased up to tens or even hundreds or thousands, it is difficult to ensure, by writing pointer control, real-time writing of input data into the FIFO; and reading pointer is complicated, as well, thereby not only leading to low circuit reliability, but also consuming massive circuit resources, in which case it is difficult to implement sequential transmission of Time Division traffic data.
Secondly, a number of streams of Time Division traffic borne on a frame may differ depending on each frame. In an extreme case, this may result in a situation where Time Division traffic data on a later frame are output to the FIFO before Time Division traffic data on an earlier frame, leading to an excessively large jitter of the Time Division traffic data, failing to meet a requirement of the communication system.